Hydraulic valve operating system



G. SIMSON March 24; 1942.

HYDRAULIC VALVE OPERATING SYSTEM Filed Aug. 29, 1940 Patented "Mar; 24; 194 2- UNITED STATES PATENT OFFICE 2.277.418 nrnaaumc VALVE oraaa'rmc srsrnM Godfrey Slmson, Toronto, Ontario, Canada Application Augmt 29, 1940, Serial No. 354,721

- Claims. (Cl. 123-90) This invention relates to hydraulic valve operating systems and more particularly to that type employed in internal. combustion engines for actuating the poppet valves thereof and my object is to devise simple means of thischaracter for so actuating the valves that they will be non-sluggish in operation. Further objects I have in mind will appear from the following description.

I attain my objects by means of the constructions hereinafter described and illustrated in the accompanying drawing in which Fig.1 is a sectional detail oi! part of an en ine showing my valve operating system;

Fig. 2 a sectional detail or a plunger in its position for fully opening a valve; and

I! moves the piston into engagement with the v in which the plunger I5 is in its initial position Fi 3 a sectional detail of a modified form of my invention. i

In the drawing like numerals of reference indicate the corresponding'parts in the different figures.

l is a cylinder of an internal combustion engine. In the cylinder is mounted a piston 2 which is connected in the usual way to a crank shaft (not shown). The latter drives'the cam shaft 3 in any well known manner. In the cylinder head 6 is guided a poppet valve 5 having the usual spring 6 disposed on the valve stem l tending to maintain the valve closed on its seat 8.

The engine cylinder I carries a fluid cylinder 9 which is supplied with oil by a duct ill from the usual pump fed oiling system of the en n A piston H actuated by a cam l2 on the cam shaft 3 forces the oil from the cylinder 9 through a fluid line it to a chamber H. .A plunger l5 operating in the chamber l4 engages the stem I of the valve to open it.

. Any suitable 'means may be employed to cut oil the oil supply duct Ill from the fluid under pressure in the fluid'cylinder 8. The piston II is provided with an annular groove i6 adapted to register with the duct l0 and a central pas-' sage ll communicating with said groove and the cylinder 9 above the piston. In this Passage is carried a ball check valve I8 which permits the oil to flow, under the pressure of the usual pump in the oiling system, through said passage, the cylinder 9, fluid line l8 and into the chamber l4. Immediately the cam l2 moves the piston II, the pressure 01 the oil in the cylinder 9 exceeds that of the oil inthe duct l0 whereby the ball check valve I8 is automatically closed and oil under this excess pressure is supplied to the with the valve 6 in its closed position, it will be noted that the upper end of the slit 20 extends above the'chamber and establishes communication between the latter and the interior of a casing 2| having a sump 22 for receiving the oil bled from the system. plunger thelower end of the slit-is closed whereas in Fig. 2, in which the plunger l5 has been moved to its flnal position in which the valve is opened, the upper end ot-the slit is closed and the lower end thereof extends below the chamber to establish communication between the chamber and the casing again. The opposite ends of the slit 20 are within the chamber to close the bleed during the movement of the plunger from its initial to final positions. The sump 22 communicates with the crank case of the engine from which the oil for the lubricating and the valve operating systems is supplied.

The plunger I5 is provided with a shoulder ,23 for engaging a stop 24 to positively limit the movement 01- the plunger in its flnal or valve opening position. A screw 25 threaded longitudinally in the plunger l6 engages the stem 1 of the poppet valve. By turning the screw, the plunger will be axially moved relative ,to the stop 24 to vary the stroke of the plunger and thusthe amount of movement imparted to the valve 5. A lock nut 39 is provided to retain the screw as adjusted.

The chamber M is provided with an annular air pocket 26. Air trapped therein is compressed by the 011 immediately pressure is applied thereto by the piston H whereby the air serves as a shock absorber until the inertia of the plunger and valve is overcome. Thereafter the air is further compressed during the movement of the plunger while the bleed means is closed. Thus when the plunger reaches its final position in which the bleed means is open, the highly compressed air assists the liquid in maintaining, the maximum pressureon the plunger l5-to retain the valve 5 in its open position while the high portion 0! the cam l2 moves past its point of contact with the piston I l.

The plunger may be provided with one or more slits 21 which are shorter than the bleed slits 20 to increase the volume of liquid spilled into the mb r is to actuate the plunger It. A spring 15 sump 2.2 when the plunger is in its'initial posi- In this position of the ating a normally closed poppet valve to open it;

tion. Any air in the line It is thus quickly expelled to prevent the formation of air looks. The cam 12 is so shaped that pressure is applied to the liquid'in the cylinder 8 immediately the high portion of the cam actuates the piston H. The volume of liquid displaced by the piston II is much greater than that displaced by the plunger l5 and thus the latter is moved rapidly towards its stop 24. After the cam 12 has been rotated to relieve the pressure 01' the oil, the valve spring 6 will close the valve 5 andat the same time return the plunger It. to its initial position.

In Fig. 3 the bleed means is controlled by the valve operating piston H which is provided with a port 28 adapted to register with the bleed 29 formed in the wall of the cylinder 9" when the piston is in its final position in which the poppet valve is opened. The bleed 29 communicates with the cylinder Q'when the piston ll' is in its initial position in which the poppet valve is closed. In this form of the invention, the plunger l5 reciprocates in the chamber l4", formed at the upper end oi. the cylinder 9, to actuate the poppet valve 5 of an L head engine. The plunger is provided with a shoulder 23" for engaging a stop 24 to limit its movement.

It will be understood that various other modifications may be made without departi'ngfrom the spirit of my invention.

What I claim as my invention is:

1. A hydraulically actuated plunger for oper ating a normally closed poppet valve to open it; a chamber in which the plunger operates; and means for bleeding said chamber,'the means comprising a slit extending longitudinally of the plunger and terminating intermediate its ends, one end of the slit being outside the chamber when the plunger is in its initial position, the other end of the slit being outside the chamber when the plunger is in its final position, both ends of the slit being within the chamber to close the bleed means during the movement of the plunger from its initialto final positions.

2. In a hydraulic valve-operating system, a cylinder communicating with a source of fluid supply; a mechanically actuated piston in said Cylinder; a normally closed poppet valve; a plunger for opening said valve;- a chamber in which the plunger operates, the chamber being in communication with the cylinder; and means controlled by one of said piston and plunger parts I for bleeding the system, the said means communicating with the exterior of the chamber to bleed the system when the poppet valve is in its initially closed position and also when said a chamber in which the plunger operates; and means controlled by said plunger for bleedin said chamber, the said means being opened by the plunger to communicate with the exterior of the chamber to bleed the latter when the plunger is in its initial position in which the poppet valve is closed and also when the plunger nears its final position in which the valve is opened, the said means being closed by the plunger during the movement of the plunger from its initial position to its final position.

4. A hydraulically actuated plunger for operating a normally closed poppet valve to open it; a chamber in which the plunger operates; means controlled by said plunger for bleeding said chamber, the said means being opened by the plunger to bleed the chamber when the plunger is in its initial position in which the valve is closed and also when the plunger nears its final position in which the valve is opened, the said means being closed by the plunger during the movement of the plunger from its initial to final positions; and an air pocket in said chamber, the air in said pocket being compressed while the bleed means is closed during the movement of the plunger from its initial to final positionsand being adapted to apply pressure to the liquid in the chamber when the bleed means is again opened by the plunger as the latter nears its final posi ion.

5. In a hydraulic valve operating system, a cylinder communicating with a source of liquid supply; a piston operating in said cylinder; a normally closed poppet valve; a plunger for opening said valve; a chamber in which the plunger operates, the chamber being in communication with the cylinder; a cam having high and low portions for actuating the piston to supply liquid under pressure to the chamber; means controlled by said plunger for bleeding said chamber, the said means being opened by the plunger to communicate with the'exterior of the chamber to bleed the latter when the plunger is in its initial position in which the poppet valve is closed and also when the plunger nears its final position in which the valve is opened, the said means being closed by the plunger during the movement of the plunger from its initial to final positions; and an air pocket in said chamber, the air in said pocket being compressed while the bleed means is closed during the movement of the plunger from its initial to final positions and being adapted to expand when the bleed means is again opened by the plunger as the latter nears its final position whereupon the air pressure is utilized to maintain the poppet valve in its open position until the low portion of the cam causes the pressure of the liquid to be reduced.

GODFREY SIMSON. 

